Press forming method and press forming apparatus for outer panel of automobile

Patent metadata

Field	Value
Publication number	US-12409489-B2
Application number	US-202118033240-A
Country	US
Kind code	B2
Filing date	Jun 9, 2021
Priority date	Oct 26, 2020
Publication date	Sep 9, 2025
Grant date	Sep 9, 2025

Abstract

A press forming method includes: moving a die toward a punch; bringing a punch side and a die side elastic bodies into contact with a metal sheet; and press forming the metal sheet, wherein an amount of protrusion of the punch side elastic body is set so that the punch side elastic body: comes into contact with the metal sheet before the punch; and becomes flush at a bottom dead center, and an amount of protrusion of the die side elastic body is set so that: the die side elastic body comes into contact with the metal sheet before the punch; and a product of: a load of the die side elastic body; and a friction coefficient between the die side elastic body and the metal sheet, becomes equal to or larger than an absolute value of a difference between tensions acting on the portions sandwiching a character-line equivalent portion.

First claim

The invention claimed is:

1. A press forming method for an outer panel of an automobile, for press forming a metal sheet into the outer panel of the automobile, the outer panel having a character-line and a panel surface portion that is continuous on both sides of the character-line, the press forming method comprising:
providing a punch, a die facing the punch, and a blank holder facing end portions of the die, wherein
the punch includes:
a ridgeline to form the character-line;
a punch side forming surface portion to form the panel surface portion; and
a punch side elastic body supported to protrude toward the die than the punch side forming surface portion so that the punch side elastic body is able to come into contact with the metal sheet, along a character-line equivalent portion corresponding to the character-line in the metal sheet, at a position away from the character-line equivalent portion, on a side larger in tension in the press forming among portions on both sides sandwiching the character-line equivalent portion, and

the die includes:
a valley-line to form the character-line in cooperation with the ridgeline;
a die side forming surface portion to form the panel surface portion; and
a die-side elastic body supported to protrude toward the punch than the die side forming surface portion so that the die side elastic body comes into contact with and press the metal sheet, along the character-line equivalent portion, at a position away from the character-line equivalent portion, on a side smaller in tension in the press forming among portions on both sides sandwiching the character-line equivalent portion,

setting an amount of protrusion of the punch side elastic body from the punch side forming surface portion so that the punch side elastic body:
comes into contact with the metal sheet before the ridgeline of the punch contacts the metal sheet when the die is relatively moved toward the punch; and
becomes flush with the punch side forming surface portion at a bottom dead center;

setting an amount of protrusion of the die side elastic body from the die side forming surface portion so that:
the die side elastic body comes into contact with the metal sheet before the ridgeline of the punch contacts the metal sheet and the metal sheet is plastically deformed when the die is relatively moved toward the punch; and
a friction force between the die side elastic body and the metal sheet becomes equal to or larger than an absolute value of a difference between tensions acting on the portions on both sides sandwiching the character-line equivalent portion when the metal sheet is press formed, where the friction force is given by a product of:
a load of the die side elastic body pressing the metal sheet at the press forming the metal sheet; and
a friction coefficient between the die side elastic body and the metal sheet;

relatively moving the die toward the punch in a state where both end portions of the metal sheet are sandwiched between the die and the blank holder;
bringing each of the punch side elastic body and the die side elastic body into contact with the metal sheet; and
press forming the metal sheet into the outer panel of the automobile, the outer panel having the character-line formed by means of the ridgeline and the valley-line, by relatively moving the die toward the punch up to the bottom dead center with the punch side elastic body and the die side elastic body both being in contact with the metal sheet.

2. The press forming method for the outer panel of the automobile according to claim 1 , wherein the punch side elastic body is movable along a press forming direction and is provided in the punch via a punch side movable body that supports the punch side elastic body by pressuring the punch side elastic body toward the die.

3. The press forming method for the outer panel of the automobile according to claim 2 , wherein the die side elastic body is movable along a press forming direction and is provided in the die via a die side movable body that supports the die side elastic body by pressuring the die side elastic body toward the punch.

4. The press forming method for the outer panel of the automobile according to claim 1 , wherein the die side elastic body is movable along a press forming direction and is provided in the die via a die side movable body that supports the die side elastic body by pressuring the die side elastic body toward the punch.

5. A press forming method for an outer panel of an automobile, for press forming a metal sheet into the outer panel of the automobile, the outer panel having a character-line and a panel surface portion that is continuous on both sides of the character-line, the press forming method comprising:
providing a punch, a die facing the punch, and a blank holder facing end portions of the die, wherein
the punch includes:
a ridgeline to form the character-line;
a punch side forming surface portion to form the panel surface portion; and
a punch side elastic body supported to protrude toward the die than the punch side forming surface portion so that the punch side elastic body is able to come into contact with the metal sheet, along a character-line equivalent portion corresponding to the character-line in the metal sheet, at a position away from the character-line equivalent portion, on a side smaller in tension in the press forming among portions on both sides sandwiching the character-line equivalent portion, and

the die includes:
a valley-line to form the character-line in cooperation with the ridgeline;
a die side forming surface portion to form the panel surface portion; and
a die-side elastic body supported to protrude toward the punch than the die side forming surface portion so that the die side elastic body comes into contact with and press the metal sheet, along the character-line equivalent portion, at a position away from the character-line equivalent portion, on a side larger in tension in the press forming among portions on both sides sandwiching the character-line equivalent portion;

setting an amount of protrusion of the punch side elastic body from the punch side forming surface portion so that the punch side elastic body:
comes into contact with the metal sheet before the ridgeline of the punch contacts the metal sheet when the die is relatively moved toward the punch; and
becomes flush with the punch side forming surface portion at a bottom dead center;

setting an amount of protrusion of the die side elastic body from the die side forming surface portion so that:
the die side elastic body comes into contact with the metal sheet before the ridgeline of the punch contacts the metal sheet and the metal sheet is plastically deformed when the die is relatively moved toward the punch; and
a friction force between the die side elastic body and the metal sheet becomes equal to or larger than an absolute value of a difference between tensions acting on the portions on both sides sandwiching the character-line equivalent portion when the metal sheet is press formed, where the friction force is given by a product of:
a load of the die side elastic body pressing the metal sheet at the press forming the metal sheet; and
a friction coefficient between the die side elastic body and the metal sheet;

relatively moving the die toward the punch in a state where both end portions of the metal sheet are being sandwiched between the die and the blank holder;
bringing each of the punch side elastic body and the die side elastic body into contact with the metal sheet; and
press forming the metal sheet into the outer panel of the automobile, the outer panel having the character-line formed by means of the ridgeline and the valley-line, by relatively moving the die toward the punch up to a bottom dead center with th

Assignees

• Jfe Steel Corp

Inventors

• Kishigami Yasuhiro

Classifications

• B21D37/10

  Die sets; Pillar guides · CPC title

• B21D24/04

  Blank holders; Mounting means therefor · CPC title

• B21D22/26 Primary

  for making peculiarly, e.g. irregularly, shaped articles · CPC title

• B21D53/88 Primary

  other parts for vehicles, e.g. cowlings, mudguards · CPC title

• B21D22/10

  Stamping using yieldable or resilient pads · CPC title